Electric Vehicles (EVs) need to be periodically recharged. This is done by connecting the EV to a charger, which receives its power from an electrical supply line. Plug-in hybrid vehicles also need to be recharged to take advantage of the lower energy costs associated with the established electrical infrastructure. As the adoption rate for these kinds of vehicles (collectively referred to herein as EVs) increases across the globe, users of EVs will have increasing needs for connecting to chargers. The power consumption characteristics of EV chargers are such that when an EV is initially being charged, the EV charger draws substantial power. Conversely, when no EV is connected to the charger, or when an EV is connected but has a “nearly full” charge or a “full” charge, very little or no power is needed by the charger.
The proportion of time the charger is drawing power and charging an EV is, in all cases, less than 100%, and in some cases, can be very low at just a few percent. While chargers can automatically switch off the charging of an EV when the EV is fully charged, the electrical supply line and other location-specific infrastructure are rated to support a generally fixed amount of power (or other related measure such as current), which limits the number of chargers, even if the chargers are not fully being utilized. The requirements of the National Electrical Code (NEC) dictate system design. Systems are designed where all load devices associated with an electrical supply line are simultaneously switched on and all are drawing power at the same time. In other words, designers of such electrical systems plan for a worse-case scenario to ensure that safety conditions and standards are satisfied.
It is conceivable that as EVs are more widely embraced by society at large, multiple chargers will be clustered in a single location, such as an apartment complex or a parking garage. If multiple chargers were to be clustered to meet such charging needs using conventional techniques, the electrical infrastructure required to support such a cluster would be cost prohibitive for the owner of the location in which the cluster is to be installed (e.g., such as the apartment complex or parking garage) because of the large up-front infrastructure investment.
Employing existing technology while maintaining compliance with the NEC limits the size of the cluster to the number of chargers that will draw the maximum line current when all are switched on simultaneously. This, in turn, limits the number of chargers deployable using the existing electrical infrastructure, even though the line load will only infrequently be fully exercised. If more chargers are desired, additional electrical infrastructure must be built out at additional cost and delay, which would impede the acceptance and ramp of EVs into the marketplace.
Moreover, if multiple chargers were carelessly connected to a single electrical supply line, the power demands on the electrical supply line would, in many cases, exceed the maximum line current of the electrical supply line, or otherwise violate safety limits of a supply line breaker associated with the electrical supply line. Such an approach could lead to personal injuries, electrical fires, or other tragedies. Thus, creating such clusters of chargers can be dangerous if done improperly, and is otherwise expensive because it usually means that additional infrastructure must be purchased and installed, including additional supply lines, supply line breakers, safety switches, and the like. This inevitably deters the wider adoption of EVs.
These are only a few of the challenges presented by conventional approaches, which are impeding the wider adoption of electric vehicle technologies, and ultimately hurting efforts for energy independence and environmental responsibility.
Accordingly, a need remains for an improved apparatus, system and method for distributing charges to EVs in a cluster environment. In addition, a need remains for prioritization algorithms for charging the electric vehicles in the cluster environment. Embodiments of the invention address these and other limitations in the prior art.
The foregoing and other features of the invention will become more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.